The vertical center line of the LED lamp installation should be the same as the longitudinal center line of the lamp arm. The horizontal line of the LED lamp installation should be parallel to the ground, and there should be no obliquity in visual measurement after tightening. The LED lamp holder is fixed firmly, the adjustable lamp holder should be adjusted to the correct position according to the design, and the wiring of the lamp holder should comply with the regulations. Connections shall not be allowed in the LED lamp arm, lamp disc and lamp pole. The piercing orifice or pipe orifice shall be smooth and burr-free. Insulating sleeve or bandage shall be adopted, and the length of bandage shall not be less than 200 mm. All kinds of nuts are fastened, gaskets and spring pads should be added. The nut must not be less than two pitches after fastening.